• Login is located in the upper right corner of all pages.

Announcement

Collapse
No announcement yet.

AC not working

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    AC not working

    I have a 2005 GMC Sierra 5.3. It started with the ac quitting while I would be driving down the road, if I stop for any reason and turned the truck off like when I would get gas, when I would restart it the air would work again for awhile. Now it won't work at all I tried to recharge it but I can't get it to take any refrigerant. When I touch the hoses they are all warm and it feels like fluid is moving through them. If I'm correct the electric fans should be running when the ac or defrost is turned on but they don't. Can anyone tell me if the ac not running causes the fans to not run or if the fans not running wont let the ac run. looking for some direction to track down the problem.

    #2
    We really need pressure and temp readings to make an assessment of the refrigerant side of things.
    The electrical side of things is going to be vehicle specific but generally yes the fans should come on when the compressor is working esp when the truck isn't moving.
    So lets start with the basics, is the compressor turning?
    Is the line to the condenser HOT?

    Comment


      #3
      Originally posted by 5Buckeye5 View Post
      Can anyone tell me if the ac not running causes the fans to not run or if the fans not running wont let the ac run.
      Typically, when the compressor operates the fans will also operate. Though some systems, especially those with multi-speed condenser fans may rely on a pressure switch to signal a demand for fan operation at a specified pressure. The compressor does not use the fans as a signal to start, rather whatever sends the signal to get the compressor going also sends a signal to get the condenser fans spinning.

      Your issue may be related to high pressure from lack of condenser fan operation, so adding refrigerant at this point would not be a good idea.

      I will look at a diagram in the morning for you. As simple as a Chevy truck can be, I still use an electrical diagram as a roadmap.

      Chris

      Comment


        #4
        I just had a similar truck in the shop today. Owner said A/C would work occasionally when he started the truck cold. Last time it worked is when he slammed the hood shut. I found the compressor clutch gap was too wide from wear. I nudged the front of the hub with my prybar and the compressor clutch engaged. Then the two electric fans started running on low speed.

        Before I tapped on the clutch hub the fans were off. As soon as I hit the hub to get the compressor to kick in, both the electric fans started. I cycled the ignition and tried the same experiment again. When the compressor kicks in the fans come on.

        Comment


          #5
          Greetings CTA. This another thread but let it be. Clutch air gaps do get too large to pull in to engage. Hence, the fans (most vehicles) will not turn on.

          If YOU are fixing this best IMO would be a new total clutch and coil depending on what it is. Some can be adjusted some can't some you can't buy just a clutch!

          Most will take a clutch tool set to do gaps are near universal best at .020 or slightly less as long as it doesn't rub when OFF at all.

          A maybe that you can rent that tool kit/set if called from parts stores FREE here for 100% deposit for return.

          Please if testing via bump test again don't use metal use rubber hose or wood taking note of which direction hub will turn or could ruin YOU or clutch - duh it will instantly spin at belt speed!
          Tom
          MetroWest, Boston

          Comment


            #6
            I was looking at the clutch this morning, and it does get a signal and it does turn on but does not engage the compressor. When the engine is off I can turn the compressor by hand if what I'm spinning is the actual compressor. Tapping on the front has no effect as far as engaging the compressor. I'm not going to do to much till I get back from vacation. I noticed that there is a spray pattern that looks like it is coming from the clutch. I'm going to try to change the clutch on the vehicle if possible so I don't have to break open the system. Thanks for all the help so far.

            Comment


              #7
              What is the gap now? Said somewhere has to or set to .020 or less. If too wide magnetic power fails to engage them. New doesn't mean it's right YOU check. Various ways they adjust gap some not meant to change stinks, To,
              Tom
              MetroWest, Boston

              Comment


                #8
                I haven't checked the gap yet. I am going on vacation til the the 29th and then I will have more time to delve into it. We will have to do without AC, its only 50 miles to Yogi Bear campground so we will endure. You members have given me some areas of direction so I'm sure I will figure it out. Everyone have a good week and I will talk later.

                Comment


                  #9
                  Most gaps can be checked by folding a standard biz card. It should be hard to fit in,
                  Tom
                  MetroWest, Boston

                  Comment


                    #10
                    Well I finally had time to work on my truck again and when I pull on the clutch it opens to about .080 and when it is in the off position it is almost closed entirely. There is all kind of rubber material that is sprayed around the area that is coming from the clutch. My concern is was the clutch destroyed by a bad compressor or did it just wear out. when it is running you can hear the clutch rubbing

                    Comment


                      #11
                      That's THE upfront problem. Most would tolerate .030 perhaps more not .080!

                      How and why? Surreal high miles still doesn't add up they wear a little just normally would have acted up long ago if gradual + normal?

                      It either locked up and somehow forced to keep rubbing - doubt that it would get glowing red hot.

                      A guess now it slipped but worked for quite a long time. Still would get hot - too hot that's excessive wear.

                      This probably has to mean compressor was taken out or harmed should go even if you could adjust that or do just a clutch and coil.

                      If your measurement is correct it's the most I've heard of!
                      Tom
                      MetroWest, Boston

                      Comment


                        #12
                        Sorry for two post not edit last one in case you read it.
                        You said you "pulled" on it OUTwards to .080. They don't pull are spring loaded to be fully OUT so I'm lost how it did more except shaft of compressor is moving out with that out hub.

                        Either way whole unit is needed. Go new if you can no remans there are too many failures this may be fine with just compressor - an exception to some rules.

                        Dump out any oil and add that much plus about 1.5 oz some into low line or port so it instantly has lube. Got that?

                        Clutch is actually just a pulley the compressor just a place to mount it then when engaged is ONE with compressor I think you follow me?

                        Two separate things going on both matter of course .

                        Season for high demand (here) should end within a month or so except for those stuck in traffic, all dressed up could be too hot in a vehicle on a cool day.

                        Both cars and trucks don't vent plain air well in fact plain "vent" is hotter than real air temp stinks IMO grew up A/C was so costly never saw a car never mind a truck with A/C!

                        Vents were actual outside air both floor and panel if vehicle was equipped. Vent (wing) windows if moving at all plenty. All that gone with no techno crap to screw up cursed a few days saved a fortune new + easier for other work without it!
                        Tom
                        MetroWest, Boston

                        Comment


                          #13
                          I am resolved to replacing everything firewall forward, Compressor, accumulator, orifice tube and condenser and flushing the evaporator. I remember the old days of wing vents on the windows and floor vents and you were right about that being enough most of the time. I'm going to have the system evacuated and remove it so I make sure I get the right parts, there are a lot of different compressors to choose from. Is there a situation where I wouldn't need to flush the evaporator. Truck has 190,000+ miles on it. Thanks for your help
                          Last edited by 5Buckeye5; 1 day ago.

                          Comment


                            #14
                            AT least blow air thru evap see what oil is like anywhere found. O tube if clean in old condenser (I think this is in it on this model) is a good sign.

                            AYOR at tossing everything it's possible to bust parts (evap) or new for a while now QC of stuff is horrible lots of assorted defective new - is discouraging,
                            Tom
                            MetroWest, Boston

                            Comment

                            Working...
                            X